PROJECT SUMMARY/ABSTRACT Very early screening for autism spectrum disorder (ASD) - sooner than the current American Academy of Pediatrics recommendation to screen at a child?s 18 and 24-month well-child visit - could result in earlier diagnosis and more children receiving treatment services at the ages when treatment has demonstrated the greatest impact. This proposal aims to provide new data on the performance characteristics of the Communication and Symbolic Behavior Scales Developmental Profile Infant-Toddler Checklist (IT Checklist), a broadband screening tool for communications delays. Approximately 500 children ages 12-15 months who attend a well child or sick visit at Boston Medical Center?s Pediatric Clinic will be screened with the IT Checklist. All parents will be asked permission to 1) complete the IT Checklist, 2) share the screening results with the child?s primary care provider, and 3) to access the child?s electronic medical record (EMR) to track future developmental screening and assessment. The performance characteristics of the IT Checklist will be assessed via a two-tiered approach: 1) comparing the scores on the IT Checklist with scores on the Parents? Evaluation of Developmental Status (PEDS) at 12-15 months and 2) comparing the scores on the IT Checklist at 12-15 months to scores on the Modified Checklist for Autism in Toddlers, Revised (MCHAT-R) at 18 and 24 months. For children who are screened with the IT Checklist, scores on the PEDS obtained at the 12 or 15 month well-child visits and scores from the MCHAT-R obtained at the 18 or 24-month well-child visits will be abstracted from the child?s EMR. This will allow researchers to assess concordance of risk identified on the IT Checklist with risk identified by the PEDS and MCHAT-R. We will present descriptive statistics regarding screening results for the entire cohort and stratified by language used to conduct the screen, child age, and parental concerns. We will stratify screening results on the IT Checklist by subscale ?language delay (LD), developmental delay (DD), and ASD. We will calculate the kappa statistic for agreement between IT Checklist and PEDS, IT Checklist and MCHAT-R, and IT Checklist and parental concern. The kappa statistic will be obtained for agreement with the IT checklist as a whole and for each of the subscales. Our final step will be to examine the performance of the IT Checklist within this largely low-income ethnically diverse population. We will conduct multivariable logistic regression to assess the relative odds of a failed screen overall and by subscale, taking into account language, child age, and parental concerns.